This invention relates to a screen device best suited to use in a projection type display device for a high-definition television (HDTV) set.
Nowadays, high-definition television sets which can provide more impact and realism in feeling than conventional television sets are being rapidly developed. Such high-definition television sets incorporate an audio system having three front channels and one rear channel (hereinafter referred to as 3-1 type 4-channel system) (e.g. "NHK TECHNICAL REPORT", 1986 11, VOL. 29, pp. 417-420).
An example of such a system is shown in FIG. 1. This system includes a front-left channel speaker 2 arranged forward on the left (of a viewer 1), a front-central channel speaker 3 arranged forward at the center, a front-right channel speaker 4 arranged forward on the right, a rear-left channel speaker 5 arranged rearward on the left, and a rear-right channel speaker 6 arranged rearward on the right. The two rearward arranged speakers reproduce the same sound.
FIGS. 2 and 3 are a front elevational view and a plan view, respectively, of the screen of a conventional high-resolution television set and the front speakers of the 3-1 type 4-channel speaker system used therewith. As shown in the drawings, this conventional high-definition television set includes a screen 7 having a front projection type display, a left side sound speaker 2, a center sound speaker 3 arranged behind the screen 7, and a right side sound speaker 4.
In this television set, television images are displayed on the screen 7, 3-channel front sound being reproduced through the speakers 2, 3 and 4 arranged behind and on the left and right of the screen 2. The reference numeral 8 indicates the frame of the screen 7.
With a television set with the above construction, since the center sound speaker 3 is arranged behind the screen 7, the screen operates as a barrier to the sound emanating from this speaker 3. Furthermore, in the case of a rear projection type display, the above-described speaker system cannot be adopted since the center speaker 3 arranged behind the screen stands in the way of rear projection. Moreover, when a larger screen is employed, the sound should be magnified accordingly so as to augment the impact and realism in feeling of the television system, resulting in large-sized speakers which occupy a relatively large floor area when installed.
It is accordingly an object of this invention to provide a screen device in which the above-mentioned problems are eliminated, i.e., a screen device in which the sound from the center speaker is not interfered by the screen and which can provide greater impact and realism in feeling even with a complete system including speakers that is reduced in size.
Another object of this invention is to provide a screen device which can be used in a rear projection type display.
The screen device in accordance with this invention is characterized in that the three kinds of front speakers are incorporated into the screen frame to which the screen is attached in the central section thereof.
Further, the screen device in accordance with this invention is characterized in that it includes, in addition to the speakers that are incorporated into the screen frame, speakers which utilize the screen itself as the diaphragm.